80 
THE VOYAGE OF H.M.S. CHALLENGER. 
2. Lateral epibranchial spines small or obsolete : — 
Macrocoeloma cutheca (Stimpson) (as figured by A. Milne Edwards). Tortugas ; 
Santa Cruz, &c. ; Florida Strait, 12 to 115 fathoms. 
Macrocoeloma laevigata (Stimpson) = Pericera curvicorna, Desbonne and 
Schra mm . St. Thomas ; Guadaloupe. 
Macrocoeloma trispinosa (Latreille). 
1 Pisa trispinosa, Latreille, Encycl. Meth. Hist. Nat., voL x. p. 142, 1825. 
Pericera trispinosa, Milne Edwards, Hist. Nat. Crust., vol. i. p. 336, 1834. 
„ „ Guerin, Icon. des. Crust., pi. viii. fig. 3, 1829-44. 
„ „ A. Milne Edwards, Crust, in Miss. Sci. au Mexique, pt. 5, p. 52, pi. xv. 
fig. 2, 1873; et synonyma. 
An adult and a smaller female is in the collection from Bermuda, and four small 
specimens (male and three females) from Bahia; collected in shallow water. 
I have examined, in the collection of the British Museum, a considerable series of 
specimens of this reputedly rare species, of different ages and of both sexes. It exhibits 
considerable variation as regards the form and direction of the rostral spines, and the 
development of the prominences of the carapace. In a large adult male from the 
Tortugas, length of carapace and rostrum 25^ lines (54 millims.), the gastric region is 
very lofty and convex, and the rostral spines straight, but somewhat deflexed, sloping 
downward in a plane with the anterior dorsal surface of the gastric region ; in smaller 
individuals the rostral spines are not deflexed, and vary considerably in length, being 
more than one-half or less than one-third the length of the carapace ; generally they are 
parallel at the base and very slightly divergent towards the tips, but in one specimen in 
the Challenger series the divergence is much greater, as in Macrocoeloma diacantha 
(A. Milne Edwards), and Macrocoeloma camptocera (Stimpson), which are perhaps merely 
varieties of Macrocoeloma trispinosa. 
Macrocoeloma septemspinosa (Stimpson). 
Pericera septemspinosa, Stimpson, Bull. Mus. Comp. Zool., vol. ii. p. 113, 1870. 
„ „ A. Milne Edwards, Crust, in Miss. Sci. au Mexique, pp. 59, 200, pi. xv. 
A. fig. 2, 1873. 
Bahia, shallow water, an adult female. 
Adult j . 
Length of carapace and rostrum, 
Breadth of carapace, about . 
Length of a chelipede, 
Length of first ambulatory leg, 
Lines. 
Millims. 
181 
41 
15J 
32-5 
16 
34 
14 
30 
